Mild Irritation
by greyslostwho
Summary: Castle/Beckett. Beckett's developing relationship with Castle. Long oneshot.


Mild Irritation

_What started out as a short oneshot is now a slightly long study (it wasn't meant to be pushing 5000 words) into Beckett's developing relationship with Castle. Beckett's POV. Totally shocked, by the way, that getting into Beckett's head seemed easier than getting into Castle's._

_Edit: I totally didn't intend on giving Alexis such trauma._

She knows it's in her nature to dislike him the moment she meets him, surrounded by the leggy blondes and drinks and bright lights. The man's wearing sunglasses indoors, for heaven's sake, and she can't deny the slight sinking feeling in her stomach – she can't deny that she was expecting Derek Storm. But she gets her first little wave of satisfaction when she arrests him, sees him blinking in the bright light of her interrogation room … they're on her turf now, in her home territory. Her irritation builds as he attempts to smooth talk his way out of being her murder suspect, but by the time they apprehend Harrison Tisdale, she's beginning to build a tolerance level.

She's not that kind of girl, but she admits being slightly tempted by his offer of spending the night together – it may be veiled, but she knows that's what it is – however annoying he might be, she's beginning to see little bits of where Derek Storm came from, and you can't deny he's charismatic, enticing. The moment she denies him, however, and leans forward to whisper in his ear, she realises it's preferable to have him eating out of the palm of her hand and _not _vice versa.

At the time, she resents Montgomery for needing to please the Mayor, the Mayor for being friends with Castle, and mainly just Castle for deciding to base a book on her and follow her around doggedly, but after a couple of cases, and although she'd never admit it to him, she begins to see the advantages to him. He does have a unique view point, and she's not going to give him any credit for it, but he's actually helped her on a number of occasions. It's this begrudging acceptance that drives her to tell him about her mother, the ring and the watch. He watches her quietly afterwards, and she thinks she sees a man behind his eyes, a man she could grow to like, rather than the man-child she's been tolerating.

They grow closer, she doesn't find it easy at first, but he does make her laugh, and he does lighten the mood a little, and there are layers to him she couldn't see at first, the daughter, the tender moments, the way his eyes look sometimes. He's not as much of an open book as she'd expected, and she finds each page she turns she finds more reasons to like him, to look beyond the ridiculous exterior.

She's not naïve, and there's jealousy in his eyes when he watches her with Will Sorenson, but she's caught up in the past and it's easier to admit still having feelings for an old flame than to try and put into words what she feels for Castle. She doesn't even see it coming when he digs up her mother's case, and it feels somewhere in between a betrayal and the nicest thing anyone's ever done for her, so she pushes him away.

He's like a child like that, she can't seem to stay mad at him for long, and his apology makes her mentally heave a sigh of relief – she can hardly admit it to herself, but she was beginning to miss him. She likes working with him, she's long beyond denying that sometimes he has invaluable advice, and she's content to be his friend, stay at arm's length, stay comfortable.

And then he goes and dedicates his book to her.

She's not even sure how you're supposed to react to something like that, but the word _extraordinary _stands out on the page and she remembers something her mother said to her when she was eight years old and they'd asked everyone in her class in school what they wanted to do when they grew up and she hadn't had a clue.

"Whatever you do, Katie, as long as you put your whole heart into it, I know you'll be extraordinary."

She's not one hundred per cent comfortable with her on-paper counterpart, but she's long gotten used to having the name Nikki Heat follow her everywhere, and she can't fail to admit _Heat Wave _is good – better than his others, even. She even considers it too successful, somewhere in the back of her mind, when Castle's offered the _British secret agent _job, and she realises he's become part of her every day, part of her normal, and she's not comfortable with losing him.

She pretends for all she's worth that his Nikki Heat three-book-deal pisses her off, but she's not even convincing herself.

She's gotten used to him.

She tells herself that's why she doesn't really like Kyra Blaine, the other KB, despite her being polite, kind, considerate. She tells herself the feeling stirring in her stomach when she watches Castle look at the other woman, when she sees the two of them kissing – that feeling's definitely irritation that his emotions are interfering with her case.

Nothing more.

She realises he knows more about how she thinks than she's comfortable with when there are tears in her eyes and he makes a childish comment, "because you're tall", and it's the only way to make her laugh, to lighten what seems like a hopeless situation. She tells herself it's because he's as good at reading people as she is, she tells herself there's nothing to read into it.

She can't keep up that façade any more when there's a man – the very same man that took the single most important thing in her life from her – pointing a gun at Castle, and she knows she's shattering so many hopes of ever finding the truth, but she can't even hesitate.

In that moment, when she weighs up the two things, and having Castle in her life is coming out higher than finding the one answer she's been searching for for ten years, in that moment she knows she's got a problem. He passes her takeout and offers her a slightly guilty smile afterwards and she's not that girl, she's never been that girl, but for a split second she's not entirely in control and she wishes – only for a second – that he'd just put his arms around her.

He does, however, climb into her burning apartment for her – and so he should, the cynical part of her thinks; he created the character this guy is killing for – and she sees a fear that absolutely terrifies her in his eyes for a moment… she's not about to decide what it means, and she's conveniently _naked, _which is reason for her to scream at him to look away, to put off the moment their eyes meet.

When he makes her pancakes that morning it's for the second time in a row, and there's a worrying comfort in the domesticity of it all, and without hardly even realising it, she's living in Castle's loft, and she's watching him first hand with Alexis, and she's struck again by the realisation that he's so much more than the face he shows most of the world. She's almost reluctant to move out.

She's always been realistic, grounded, and on paper Tom Demming is perfect for her, and so she goes there with a keenness she wouldn't have had a few years ago. It's almost like she's trying to prove a point, whether to herself or to the rest of the world she's not sure, but Tom's nice, and he likes her, and they're good together, and there's something in her always watching for the flicker of jealousy in Castle's eyes.

She thinks she must have been imagining it when she has a moment of temporary insanity – her talk with Esposito had nothing to do with it, there must have been something in the water that day – and breaks up with Demming, and Castle, infuriatingly oblivious, wanders off to the Hamptons all summer with his ex-wife.

Looking back, she thinks that was breaking point. Sure, he eventually weasels his way back into her life, back into her work, and back into her heart. (She's not sure he ever left, but that's what she tells herself.) There's a distance between them, though, that wasn't there before. A distance defined by the walls she's put up and the space she puts between them, and she almost realises she's doing it, but she never comes close to stopping herself. Castle hurt her, when she wasn't even aware he was close enough to her to do that, and that's not something she's prepared to risk happening again. They stay friends, both of them standing firmly either side of an invisible line, and there are other Demmings and other Ginas and they both stay somewhere between pretending not to notice and pretending not to mind.

She goes with him to take Alexis to Princeton, because he's been begging her to, because he's been looking so sad lately. She finds herself a coffee shop and sits in the window whilst he takes his daughter in, sizes up the dorm room (and the male company, she assumes), and says his goodbyes. They drive home in a sort of companionable silence, Castle staring slightly blankly ahead, Beckett knowing exactly what he needs.

He invites her in when they get back to New York – Martha's in London doing something on the West End, and they're both currently single – giving her those puppy dog eyes and no one will miss them, and no one will know, so she says yes. He opens a bottle of wine and she doesn't protest, because she's been this comfortable around him for what seems like forever, and she can't count the number of times she's needed him to make her smile – she wants to pay him back.

They open a second bottle, and she's beginning to feel a little light-headed, and she knows she's talking ten to the dozen, but she doesn't want to stop. She wants to sit here, on Castle's couch, laughing, their knees occasionally brushing one another, and watch the world spin around them.

She's pretty sure that's the moment the enormity of what she feels for him dawns upon her, and surprisingly (and maybe because, deep down, she's known all along) it doesn't scare her too much. She doesn't get up to leave until the early hours of the morning, and when she does, and he says something about how lonely the house feels without anyone else in it, she puts her hand on his arm, thumb moving slightly, stroking a slight path. They're very close, all of a sudden, standing at the bottom of the stairs in his loft, and the world is silent around them.

She says "Castle" at the same time as he says "Beckett", and her eyes find the floor, a sudden flush rising in her cheeks, because she realises she's too afraid to take the step, and what it all comes down to in the end is how afraid she is of losing him.

"Kate…" he breathes, and when their eyes meet she realises they both know she's never going to close the gap between them, and so he's looking at her with a question in his eyes, face inches away from hers. She gives an almost imperceptible nod, and he crosses into her space, firmly and confidently pushing his lips against hers.

'Weak at the knees' is not a term she's ever thought she would use to describe herself, but her legs buckle underneath her and she finds herself fully in his arms, hands clasped behind his neck, body flush against his, as his mouth moves over hers. Her heart is thumping and her blood is roaring in her ears… this is something she's denied herself for too long. She's completely unashamed as she moans slightly into his mouth, pulling him even closer, curling her fingers into his hair.

When he pulls back, she does nothing but smile widely up at him, their bodies so close that she can feel his heartbeat racing, matching hers, biting her lip slightly as he rests his forehead against hers. He says something, but she's not really got any idea what he's saying, she's too busy leaning up and kissing him again, a permanent smile fixed on her face.

He makes her stay in the guest room that night, and she doesn't argue for long, his puppy dog eyes are even more effective when they're punctuated with kisses, when his hands are on her waist. She spends most of the night lying awake, her whole body tingling with a mixture of fear and desire, her mind wandering every now and again to the possibilities if she simply got up and walked a few paces towards Castle's bedroom.

As it is, he takes her on dates, ice-skating at the Rockefeller centre, dining in exclusive restaurants with celebrity guest lists, walking in Central Park. They keep the relationship quiet for a few weeks, then Ryan catches them making out in an interrogation room, and denying it is completely futile. She doesn't end up in his bed for almost two months – Castle's intent on 'wooing' her – and when she does, it's all the better for waiting. She wakes up, arms and legs all wrapped up in his, with the sun streaming through the window, and she kisses him awake with a smile on her face. He wriggles a little, reluctant to stir, but within moments he's kissing her with a characteristic fervour, morning stubble chafing lightly against her skin.

She takes him to meet her father, she's never seen him quite so nervous, shifting from one foot to the other, speechless for the first time in his life. They hit it off right away, however, and she soon finds herself sitting, tucked slightly into Castle's side, in the restaurant she and her father had always loved, listening to the two men roaring with laughter. Her father catches her hand whilst Castle's driving the car round to meet her, a smile on his face the first one she's seen meet his eyes in a long time, and says, "I like this one, Katie… and your mother would have loved him…" and tears well up in her eyes.

Alexis comes home for Christmas, and Castle insists she and her father share the occasion with them, and there's board games and eggnog and mountains of food, and she hasn't had a holiday like this, so carefree, so _happy, _since before her mother died. They kiss under the mistletoe and Alexis cheers and she finds herself curled up in Castle's arms with a makeshift family around her as evening turns into night and night turns into morning. Watching A Wonderful Life, her Christmas cliché complete, Alexis falls asleep with her head on her shoulder, and she wraps her fingers in Castle's and closes her own eyes.

The first public pictures of them that arrive are in the spring, and Castle and Martha tell her not to read the articles, but she can't help it, and some of them are flattering, some of them are not. She likes the picture, though – someone's caught them walking hand in hand, and she's laughing at something he's saying, and it goes further to defining how she feels about him than she can put into words, so she frames a small copy for her desk. When he sees it, whilst he's swinging childishly in circles on her desk chair, he gets up and kisses her in the middle of the Precinct, looks around to make sure no one is watching and whispers, "I love you" in her ear. There's something in the look he gives her afterwards that reassures her he's not looking for a reply, so she simply sits there, stunned, until he goes to make coffee.

Her mother's case snowballs through their homemade happiness again that summer, and it reduces them to their worst – she's screaming at him for reasons she doesn't even understand, he storms out of her apartment one night, slamming the door behind him. (She finds out later that he sat in the lobby of her building all night, and it brings tears to her eyes.) The catch the people behind it in the end, after weeks of searching, and when it's finally over, when she's finally told her father the truth – Castle stands slightly behind her as she chokes it out, one hand on her shoulder – she asks Castle to come with her and drives out to the cemetery and leaves yellow roses on her mother's grave. She sees Castle choke up when he realises where she's brought him, and as the sobs rack through her body she whispers, "It's over now, Mom, it's over,"; he wraps his arms wordlessly around her and holds her as close as he can, waiting out the wave of pain they're both riding.

When she's finished crying, she looks up into his big, sad eyes and she only has one thing to say. "I love you, too." She breathes, leaning her forehead against his, the few remaining tears falling silently down her cheeks. His breath audibly catches and he kisses her forehead, holding her so tightly she can feel his fingers gripping her arms.

"I'm so sorry… I'm so sorry you had to go through all this…" his voice is a strangled whisper in her hair. She shakes her head, threading her arms around his neck.

"It's… I… thank you so much for everything you've done, Castle…"

She stands there with him, like that, for a long time.

That's the same year Ryan gets shot by a suspect, and she's standing so close to him at the time his blood creates a sordid pattern across the front of her white shirt. Esposito takes down the shooter without a second thought, and she radios for back-up, for an ambulance, her whole body shaking.

Ryan has massive internal bleeding, the bullet tearing through his abdomen, and they sit in the hospital waiting room for hours, Esposito with his arm around a sobbing Jenny, a stony-faced Captain Montgomery and Castle wraps his fingers through her, and neither of them says a word.

Ryan pulls through, miraculously, and the first thing he says to Jenny when she goes to see him is, "Will you marry me?".

The words haunt her for weeks, and when she talks to Ryan about it, he doesn't put her any more at ease. He tells her, his eyes wide and solemn, that as he was bleeding out on the street; his thoughts went straight to his regrets – that he hadn't shown the world that he wanted to spend the rest of his life with the woman he loved.

She thinks about this when she lays in Castle's arms, his light snoring creating a slight vibration through her back. Slowly, she turns in his arms and sits up, shaking his shoulder gently, waking him. He blinks through the half-light, rubbing the sleep from his eyes.

"You all right?" he stutters, eyes half closing again.

"I think we should get married." She whispers, and it's pretty clear from the way Castle's jaw drops open and the fact that he jolts upright that he's fully awake, all of a sudden.

"I'm dreaming." He murmurs to himself, making her laugh slightly.

"No." she breathes, running her left index finger down his cheek, along his jawline, "I… I don't want to regret not showing you, not showing everyone I want to spend the rest of my life right here, with you."

She's never seen Castle cry before, but tears spill out of his eyes and he wipes them away fiercely, holding her by the shoulders, at arm's length, staring right into her eyes. "You're serious?" he whispers, and she knows how much he's resting on this, and she realises in that moment how much he loves her.

A single tear runs down her own cheek as she nods, biting her lip, her heart thumping in her chest. This isn't her, this isn't _Beckett, _this is entirely the person he's made her.

"I would have asked you, you know, if I thought you'd have said yes…" he frowns, "I'm sorry, I'm doing this all wrong… you never fail to surprise me, you really are extraordinary, Kate Beckett…"

She grins, and leans forward and kisses him lightly, face lingering close to his, "Is that a yes, Castle?"

He cocks his head to one side, the familiar mischievous glint in his eye. "I don't believe you actually asked me a question…"

She raises one eyebrow, but is unable to keep the grin from her face. "I'm not getting down on one knee, Castle, I'm naked."

She sees him open his mouth to make some lewd comment but he apparently thinks better of it, and continues staring at her, looking slightly bewildered.

"Richard Castle, will you marry me?" she murmurs, so low that he struggles to hear it. But he smiles, widely, and pulls her into his arms.

"Of course." He whispers into her hair before pressing his lips against hers.

She marries him in the summer, and it's a small wedding, with only Alexis and Lanie as bridesmaids, Ryan and Esposito sharing the best man responsibilities, Martha and her father vying for the loudest cheers. She wears white, but nothing sparkly and she makes Castle tear up when she looks into his eyes and says "I do". He jets the pair of them off to some remote part of the Caribbean afterwards, and they lounge on white beaches for two weeks, content in only one another. He handwrites chapters of the final Nikki Heat book laid on his towel beside her, and Nikki and Rook don't quite get married but there's definitely _something _there – she doesn't mind, she's long since surpassed her crime-novel doppelgänger. He dedicates _The Heat of the Moment _to her, Martha and Alexis, and promises her to shelve Nikki Heat for good, find himself another crime-fighter.

Alexis turns up on the doorstep one night, soaking from the rain, tears streaming down her face. Beckett's been giving one of the publicity dinners a miss – stomach flu – and for a moment she freezes as her step-daughter falls forward, sobbing into her arms, her boyfriend of two years having been killed in a freak car accident. She calls Castle straight away, but the NYC traffic takes him an hour to get home, and she makes Alexis sweet tea and rocks her in her arms (she knows none of this will really make it any better, but she knows, for past experience, it's nice to have someone try) until her father comes through the door. She sits back then, lets Castle take over, but later that night, Castle snoring beside her, she slips into the younger girl's room, finding her sitting there in the dark, hugging her knees to her chest, and she sits next to her, not saying a word, and Alexis takes her hand.

"I love you, Kate." She whispers, and tears spill down Beckett's face, for this girl who doesn't deserve this.

Turns out the stomach flu is something else entirely, and both Alexis and her father hold one of her hands as she gets her first sonogram. After everything that's happened, Alexis has decided to take a year out from Princeton, and with the overwhelming fear that's accompanying the overwhelming joy about this baby, it's comforting to have her around. Esposito and Ryan fawn over her like little girls, want to see the pictures, and Montgomery puts her firmly on desk duty, despite all her protestations – and Castle smiles smugly at her. He's adoringly overbearing, making her everything she fancies on a whim, fluffing cushions on the couch before she sits down, offering her a hand in and out of every cab they take. He's taken to kissing her stomach, too, and although she'd always thought it a hideous cliché, it almost makes her tear up after a long day, and although she blames the hormones, it warms her inside. Alexis throws herself headfirst into helping preparation for the baby – and there's a quiet acceptance between the two women that this is what she needs, this is her way of coping.

They discuss names, her and Castle, but it always travels from indecision to bickering to argument and then back again, so Alexis and Lanie take it in turn to moderate the discussions. Castle pulls her pigtails, calling out the loudest, most theatrical names he can think of, just to irritate her, and she sulks in response, refusing to tell him her ideas. When the ultrasound technician tells them they're expecting a boy, she would have thought that would reduce the arguing by half, but it only seems to escalate it. He tells her sincerely, however, when they're sat on the couch, her feet in his lap, six months through the pregnancy, that he's happier than he's ever been, and she leans across to kiss him, stunted by her ever-expanding stomach, and they both laugh and grip each other's hands tightly and she can't wipe the smile off her face.

They name him Matthew, in the end, and he's ten days late – she blames Castle's lack of punctuality – and has a good pair of lungs – she blames Castle's need to fill every silence. She is entirely to blame, however, for his dark eyes and feathering of chocolate hair, and she loves him the moment he enters the world, despite the 36 hours of labour, despite the burning agony, despite the darkening of her vision. She loves him a little more when Castle holds him and Alexis leans over to kiss him on the forehead, and then they both turn to look at her with tear-filled eyes.

Having a baby in the loft is certainly a dynamic that takes some getting used to, but with Alexis keen to help whenever and wherever she can, and Castle refusing to continue his shadowing at the Precinct whilst she isn't there, Beckett finds she couldn't be happier. She doesn't sleep regular hours anymore, has taken to not looking the mirror for fear of what she might see, and she's not sure she remembers the sound of silence, but she'll still stand and watch Matthew sleep, the way she's caught Castle doing with Alexis even now, watch his tiny chest move with every breath, each one a miracle in its own right, her son, so fragile and strong. One night, when she'd thought the whole apartment was asleep, leaning against the doorframe of the nursery, she feels Castle's arms snake around her waist, feels his lips on the back of her neck.

"Kinda overwhelming, isn't it?" he breathes, and she leans back into him slightly, feeling his heart beat through the thin cotton of her old NYPD shirt, "The thought that you made a person…"

She turns her head slightly, not taking her eyes off her son, _their son, _and presses the side of her face into his neck, her lips brushing his skin. "We made a person." She whispers, and his arms tighten around her waist, his breath hitches in his chest. She knows they're both silently telling one another how in love they are, and this moment doesn't need either of them to speak.

When her son smiles for the first time, his father's written all over his face, and she and Castle spend the whole day trying for a repeat performance. Alexis goes back to Princeton in the fall, slightly older, slightly wiser and much, much stronger. She hugs Beckett and Castle, all business and nonchalance, but cries when she kisses her little brother goodbye. Beckett takes Matthew into the Precinct, and Ryan and Esposito coo over him like a couple of aging grandmothers, and Montgomery gives her a proud, one-armed hug. Matthew crawls and walks and speaks like no time has passed at all, and she goes back to work and spends her days waiting for the moment she can walk back through the door and see her husband and son again. She catches herself with tears in her eyes one evening after a particularly long and hard case – Esposito narrowly missed a bullet to the head, Lanie was receiving threatening letters – and Matthew snowballs into her the moment she opens the door, toddling towards her, and she swings him through the air with a smile on her face. Castle closes the door behind her gently, wraps the two of them in his arms, presses a kiss to her hair. They're everything she needs.

Castle – who started as her mildly annoying, unbearably arrogant, excitable man-child - has given her something she thought she'd never have again.

A family.

FINIS


End file.
